This invention relates generally to forage harvesters and, in particular, to forage harvester row crop attachments.
U.S. Pat. Nos. 4,397,134 to H. N. Lausch et al and 4,086,749 to J. G. Greiner et al disclose typical row crop attachments for forage harvesters. These attachments include a plurality of row crop divider units arranged side-by-side on a base frame to define crop conveying paths through which gathering chains pass. Rotary knives are provided adjacent an entrance of each conveying path for cutting off crop material close to the ground before it is conveyed rearwardly through the conveying paths by the gathering chains. Each gathering chain is wrapped around a drive sprocket and two idler sprockets with one of the idler sprockets being located in an extended position forwardly of the rotary knives. Spring loaded adjustment mechanisms supported by heavy framework are used to adjust the tension and take up the slack in the gathering chains. A drawback of the row crop attachments disclosed in the Lausch et al and the Greiner et al patents is that the gathering chain adjustment mechanisms are associated with the idler sprockets that are located in the forwardly extended positions. This results in the heavy framework supporting the gathering chain adjustment mechanisms being located ahead of the rotary knives (in the direction of travel during normal operation) where it has a tendency to knock down crop material before it can be cut off.